Differentiation of granulosa cells (GC), while highly dependent on pituitary follicle-stimulating hormone (FSH), is also affected by factors which can act locally to modulate responsiveness of the cell. In addition to the known roles of various peptides and growth factors (intragonadal regulators), recent evidence supports the potential involvement of yet another class of factors, the cytokines (factors produced by activated immune cells) as modulators of GC function. Thus, the overall goal of the proposed studies is to further characterize the biochemical nature and biological actions of these progestin stimulatory and estrogen inhibitory factors (PSF and EIF) in the processes of GC differentiation. Experiments are designed to answer 3 basic questions: 1) Do PSF and EIF directly affect GC differentiation? 2) What is the cellular source (s) of PSF and EIF and does their ability to be produced depend on physiological status? and 3) What are the biochemical characteristics of PSF and EIF in GC differentiation will be determined by examining the direct effects of these factors on acquisition of steroidogenic capacity and induction of LH/hOG receptors in the presence and absence of FSH. The cellular source of PSF and EIF will be determined by monitoring for the presence of these factors among the cytokines released by purified lymphocytes (T and B) and macrophages. The production potential of PSF and EIF will be assessed as it relates to age, gender and ovarian steroids. Biochemical characterization of PSF and EIF will be accomplished using standard methodology for protein purification followed by amino acid analysis and primary sequence determination. In summary, these studies will provide knowledge of the role of PSF and EIF in GC differentiation; moreover, they will begin to define a cytokine- mediated system which may act in concert with pituitary hormones and other intragonadal factors to regulate ovarian processes. Information gained will also provide a better basic for understanding reproductive dysfunctions associated with immunological disorders as well as for the development of novel diagnostic and therapeutic regimens for fertility control.